Method and apparatus for drawing and crimping yarn

ABSTRACT

A stuffer crimper having feed rolls to feed yarn thereto and spaced draw rolls in advance of said feed rolls and a take-up roll disposed between the draw roll and the stuffer crimper and driven at a rate to maintain the yarn received from the draw roll under a tension adapted to prevent slippage on the draw roll and to deliver yarn to the feed rolls at a tension sufficiently low to avoid undesirable heating of the yarn in the bite of the feed rolls and damage to the yarn caused by high feed roll pressure. A cooling station is disposed between the draw rolls and the feed rolls to cool the yarn in advance of the crimper. The feed rolls have air passages and air vanes to induce the flow of cooling air through the passages as the rolls rotate.

waited States Patent 1191 McKinney Sept. 2, 1975 METHOD AND APPARATUS FOR DRAWING AND CRIMPING YARN Donald W. McKinney, New Castle, Del.

[73} Assignee: Joseph Bancroft 8L Sons (10.,

Wilmington, Del

[22} Filed: Dec. 28, 1973 [21] Appl. No.: 429,151

Related US. Application Data [63] Continuation of Ser. No. 95,721, Dec. 7, 1970,

abandoned, which is a continuation-in-part of Ser. No. 838,590, July 2, 1969, abandoned.

[75] inventor:

3,292,231 12/1966 Epstein .1: ..28/1.6

3,296,680 1/1967 lwnicki et a1. 28/1.7 3,337,930 8/1967 Aelion et a1 28/1 .6 3,341,913 9/1967 Jenkins et a1... 28/l.7 X 3,431,609 3/1969 Satterwhite 28/ 1.6 3,503,104 3/1970 Satterwhite 28/1.7 3,553,803 l/l97l Buschmann et a1. 28/l.6

Primary ExaminerRobert R. Mackey [5 7 ABSTRACT A stuffer crimper having feed rolls to feed yarn thereto and spaced draw rolls in advance of said feed rolls and a take-up roll disposed between the draw roll and the stuffer crimper and driven at a rate to maintain the yarn received from the draw roll under a tension adapted to prevent slippage on the draw roll and to deliver yarn to the feed rolls at a tension sufficiently low to avoid undesirable heating of the yarn in the bite of the feed rolls and damage to the yarn caused by high feed roll pressure. A cooling station is disposed between the draw rolls and the feed rolls to cool the yarn in advance of the crimper. The feed rolls have air passages and air vanes to induce the flow of cooling air through the passages as the rolls rotate.

8 Claims, 5 Drawing Figures PATENTEDSEP 2% 3.902.231

SHEET 1 [IF 2 HNVENTOR ONALD W. Mc KINNEY mfpfj ATTOIRN EY PATENIED EP 2 m5 SHEET 2 BF 2 mvmma DONALD W. McKINNEY ATTORNEY METHOD AND APPARATUS FOR DRAWING AND CRIMPING YARN INVENTION BACKGROUND This application is a continuation of application Ser. No. 95,72lfiled Dec. 7, 1970, now abandoned, which application is a con'tinuation-in-part of application Ser. No. 838,590 filed July 2, 1969, now abandoned.

This invention relates to a method and apparatus for drawing and crimping yarn and more particularly to a method and apparatus of the above type wherein the temperature and tension of the yarn is controlled in accordance with the yarn requirements.

An object of the invention is to provide, in apparatus of the above type, novel and improved means for cooling the yarn between the drawing and crimping stages to the temperature required for efficient crimping.

Another object is to provide improved means for cooling the feed rolls of a stuffer crimper.

Another object is to provide means for controlling the rates of feed of the yarn in the drawing and crimping zones in a manner to provide for the inherent shrinkage of the yarn after drawing.

Another object is to provide improved means for controlling the yarn slippage between the draw rolls and feed rolls.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

In accordance with the present invention the yarn, which is fed to the 'stuffer crimper at a high rate such as 1,000 yards per minute, is first drawn between two sets of draw rolls either in heated or in cooled state. In either case the heat generated during drawing results in the yarn being discharged from the drawing stage in a heated condition.

On the other hand the yarn should not be fed to the feed rolls of a stuffer crimper at an excessive temperature as the yarn tends to soften under the pressure of the feed rolls which, themselves, are usually hot due to the friction of the yarn, particularly in the case of feed rolls rotated at high speeds.

The invention accordingly provides for passing the yarn through a cooling stage in advance of the feed rolls. Such a stage may comprise a multipass air cooling station or a water mist which cools'and moistens the yarn but does not wet the same to an undesirable extent.

Since the yarn on the final draw rolls is necessarily under a high tension and must be fed to the feed rolls of the stuffer crimper under relatively low tension to avoid excessive heat and'yarn damage caused by high feed roll pressure a substantial reduction in tension must take place between the final draw rolls and the feed rolls. This reduction in tension may result in yarn slippage on the draw rolls.

Take-up rolls are disposed between the draw rolls and the feed rolls and are driven at a rate to maintain the yarn between the draw rolls and the take-up rolls under a tension suited to avoid slippage of the yarn on the final draw rolls. The relative rates of the take-up rolls and stuffer crimper feed rolls are such that the stuffer crimper feed roll pressure may be maintained at a level below that at which excessive heat or yarn damage occurs.

Cooling means is also provided for the feed rolls. This may take the form of cooling passages in the rolls coupled with air vanes associated with the feed rolls for inducing an air flow through such passages.

The nature of the invention will be better understood from the following description, taken in connection with the accompanying drawings in which a specific embodiment has been set forth for purposes of illustratlOn.

IN THE DRAWINGS FIG. 1 is an elevation, partly in section, of yarn drawing and crimping apparatus embodying the invention;

FIG. 2 is a detail perspective view of a feed roll showing the cooling passages and vanes;

FIG. 3 is a detail view of a feed roll illustrating another embodiment of the invention;

FIG. 4 is a section taken on the line 44 of FIG. 3; and

FIG. 5 is a broken elevation of a spray cooling chamber for use in the system of F IG. 1.

Referring to the drawings more in detail the invention is shown as comprising a first pair of draw rolls 11 and 12 around which a yarn 13 is wrapped either in a hot or cold state. After passing around the first set of draw rolls the yarn passes around a second set of draw rolls 14 and 15. The draw rolls may be heated in the usual manner by means such as steam supplied through pipes 98 and are indicated as being driven by separate motors l6 and 17 which are so regulated that the two sets of rolls operate at relative rates adapted to produce the desired amount of stretch in the yarn as it passes therebetween. Independent control means such as potentiometers for each motor may be provided to control the rates and to vary the feed ratio as desired.

It is to be understood that the rolls of each pair may be driven in unison or one of the rolls of each pair may constitute an idler roll and these rolls may be relatively inclined so as to facilitate the spacing of the wrapped yarn therealong.

From the draw rolls l4 and 15 the drawn filaments pass around a pair of take-up rolls 18 which are driven by suitable means indicated as a motor 19 at a rate adapted to compensate for shrinkage in the filaments and suited to maintain the yarn under a tension which substantially eliminates slippage of the yarn on the draw rolls.

Since the draw roll surfaces are necessarily smooth only a limited amount of friction can be obtained by wrapping the filaments around the respective rolls. The take-up rolls thus introduce a positive feed of the yarn which compensates for the limited yarn friction which may be inherent in the draw rolls and thus reduces the slippage which might otherwise take place.

From the take-up rolls 18 the filaments are passed through a multi pass air cooling stage 20 comprising a plurality of rolls 21 arranged for the passage of the filaments around the successive rolls in contact with the air for a sufficient length of time for the desired cooling to take place. From this cooling stage 20 the filaments pass to the feed rolls 25 of a stuffer crimper 27 of any standard type containing a heated crimping and setting chamber wherein the yarn is crimped and heat set as it is forced into the crimper against a mass of previously crimped yarn held under compacting pressure therein.

The core 30 of crimped yarn passes through a cooling cage 31 wherein the yarn is cooled to a temperature below the setting point and is then extracted over a guide 32 and tension gate 33 and around a guide 34 to be wound onto a package 37 which may be rotated by a roll 38 which is driven by a motor 39.

Between the take-up rolls 18 and the cooling stage the tension of the yarn may be sensed by a feeler 40 carried on an arm 41 attached to the shaft 42 of a rotary potentiometer 43 so that the position of the potentiometer is varied with the tension of the yarn. The potentiometer 43 is connected by a lead 99 to control the speed of a motor l00 which drives the feed rolls 25 so as to maintain the yarn at a predetermined tension as it is fed to the feed rolls 25.

While the potentiometer control has been shown it is obvious that other types of speed control devices may be used for controlling the rates of the various rolls.

Since the pressure of the feed rolls required to minimize slippage of the yarn in the bite is determined by the tension of the yarn supplied thereto and since excessive pressure produces an undesirable amount of heat in the yarn, the rate of the feed rolls with respect to the take-up rolls 18 is maintained at a value which, taking into account the shrinkage due to cooling reduces the tension to a value such that the pressure of the feed rolls on the yarn does not produce excessive heating.

The feed rolls are shown as having a plurality of axial passages which are inclined with respect to the axis of the rolls so as to induce a flow of air through the passages as the rolls rotate. A set of air vanes 51 is mounted on the shaft 52 of each roll. These vanes extend generally radially from the shaft and along the end surface of the roll between the opening of the passages 50. The vanes are inclined forwardly in the direction of rotation of the roll to act as scoops for forcing air through the passages as the rolls rotate. Additional vanes 53 are disposed adjacent the opposite end surface of the feed rolls and are inclined so as to create a zone of reduced pressure as the rolls rotate and thereby assist in inducing a flow of cooling air through the roll passages 50.

It is to be understood that the air cooled feed rolls may be used in connection with a stuffer crimper of various types and is useful for maintaining desired temperature conditions when the yarn is fed from a package in unheated condition as well as for preheated yarns as it prevents the feed rolls from becoming excessively hot during operation.

The dwell of the yarn in the cooling cage and the exposure of the yarn to the ambient air between the discharge end of the cooling cage and the winder is selected to cool the yarn before winding to a temperature such that the crimp is not permanently lost while the yarn remains on the winding in substantially straight form but is readily restored by preheating while in the tensionless state.

A sensing member rests upon the end of the core in a cooling cage 31. A bracket 61 pivoted at 62 is formed with a yoke 63 which extends on opposite sides of the member 60 and is pivoted thereto by pins 64 on the element 60 riding in slots 65 in the yoke portion 63 of the bracket 61. The bracket 61 engages a pin 66 on a sprocket 67 which is connected by a chain 68 to a sprocket 69 on a shaft 70 of a potentiometer 71 which is connected to control the operation of the motor 39 which drives the winder 38.

The arrangement is such that the speed of the winder is varied in a sense to maintain the end of the core at a constant level in the cooling cage.

In the embodiment of FIGS. 3 and 4 a feed roll is shown as having a set of parallel passages 81 disposed around its axis. A semicylindrical vane 82 is inserted in the entrance end of each passage 81 with its end portion projecting outwardly beyond the end of the roll 80. The projecting ends 83 of these vanes 82 are attached to a ring 84 and are arranged with their open sides facing the direction of rotation of the roll. A similar set of semicylindrical vanes 86 are disposed in the opposite ends of the passages 81 with their projecting ends 87 attached to a ring 88 and with their open sides facing rearwardly of the direction of rotation.

In this embodiment the vanes 82 serve as air scoops to produce air flow through the passages 81 as the roll 80 rotates. The vanes 86 at the discharge end of the passages produce a reduced pressure for assisting the air flow. These latter vanes may be omitted if not required in any particular instance. The vanes may be adjusted axially so as to produce the desired air flow for the cooling required. They are frictionally held in adjusted position but may be positively secured to the shaft 89 of the roll 80 if necessary.

In some cases the passages 81 may be inclined in the direction of rotation of the roll or may be made helical although a straight passage as shown is usually more convenient to produce.

It is to be understood that rolls 80 of FIGS. 3 and 4 may be substituted for the rolls 25 of FIGS. 1 and 2.

FIG. 5 shows an alternate type of cooling stage which can be substituted for the air cooling stage 20 of FIG. 1. In this embodiment a cooling chamber 90 is shown containing an atomized mist of water vapor supplied from a header 91 having perforations 92 for the discharge of the mist and connected to a supply pipe 93.

It is to be understood that the form and embodiment of the invention herein shown and described is to be taken only as a preferred representation of the invention and that various changes and modifications in the arrangement of the components, parts, units, etc. may be resorted to without departing from the spirit or scope of the appended claims.

What is claimed is:

1. Apparatus for crimping yarn comprising:

.draw rolls for engaging said yarn, said draw rolls i being driven at such a rate as to apply to said yarn a first tension of such magnitude as to draw said yarn to a predetermined degree,

take-up roll means disposed adjacent to said draw rolls for receiving said yarn exiting from said draw rolls, said take-up roll means positively engaging said yarn and being driven at such a rate as to apply to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls,

a stuffer-crimper having a crimping chamber and feed means for receiving said yarn from said takeup roll means and feeding said yarn into said crimping chamber at a predetermined tension, said yarn between said take-up roll means and said feed means being subjected to a third tension dependent upon the rate of said feed means and the inherent shrinkage of said yarn after drawing, said take-up roll means isolating said first tension from said third tension whereby said first tension is maintained substantially constant in the face of variances in said third tension.

tension responsive means interposed between said take-up roll means and said feed means for sensing said third tension, said tension responsive means being operatively interconnected with said feed means to vary the rate of said feed means if said third tension varies from said predetermined tentake-up roll means and said feed means for sensing said third tension, said tension responsive means being operatively interconnected with said feed means to vary the rate of said feed means if said sion to maintain said third tension substantially 5 equal to said predetermined tension, and

cooling means interposed between said take-up roll means and said feed means for cooling said yarn prior to engagement by said feed means.

2. The apparatus of claim 1 wherein said cooling means comprises a multipass air cooling station to maintain said yarn in contact with the surrounding air for a period to effect cooling.

third tension varies from said predetermined tension to maintain said third tension and said predetermined tension substantially equal.

5. The apparatus of claim 4 wherein said tension responsive means comprises a pivoted arm engaging said 10 yarn and movable with the slackness of said yarn.

6. The apparatus of claim 4 wherein said draw rolls are heated.

7. The apparatus of claim 4 wherein said take-up roll The apparatus of clam 1 wherein Said Coolmg means are operable independently of said draw rolls.

means comprises a cooling chamber having means for 8. A method of crimping yam comprising the steps supplying water mist through which said yarn passes. of

4. Apparatus for crimping yarn comprising:

draw rolls for engaging said yarn, said draw rolls being driven at such a rate as to apply to said yarn a first tension of such magnitude as to draw said yarn to a predetermined degree,

take-up roll means disposed adjacent said draw rolls for receiving said yarn exiting from said draw rolls, said take-up roll means positively engaging said yarn and being driven at such a rate as to apply to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls,

a stuffer-crimper having a crimping chamber and feed means for receiving said yarn from said takeup roll means and feeding said yarn into said crimp- 3 ing chamber, said yarn between said take-up roll means and said feed means being subjected to a third tension dependent upon the rate of said feed means and the inherent shrinkage of said yarn after drawing, said take-up roll means isolating said first tension from said third tension whereby said first tension is maintained substantially constant in the face of variances in said third tension, and

tension responsive means interposed between said drawing said yarn between sets of draw rolls to a first tension,

positively engaging said yarn immediately upon exit from said draw rolls and applying to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls,

feeding said yarn into a crimping chamber at a third tension of predetermined level dependent upon the rate of yarn feeding and the inherent shrinkage of said yarn after drawing, said third tension being isolated from said first tension whereby said first tension is maintained substantially constant despite variances in said third tension,

sensing the actual tension on the yarn between said positive engagement thereof upon exit from said draw rolls and said crimping chamber,

comparing said actual tension to said predetermined third tension, and

varying the rate of said feed means to keep said predetermined third tension and said actual tension substantially equal. 

1. Apparatus for crimping yarn comprising: draw rolls for engaging said yarn, said draw rolls being driven at such a rate as to apply to said yarn a first tension of such magnitude as to draw said yarn to a predetermined degree, take-up roll means disposed adjacent to said draw rolls for receiving said yarn exiting from said draw rolls, said take-up roll means positively engaging said yarn and being driven at such a rate as to apply to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls, a stuffer-crimper having a crimping chamber and feed means for receiving said yarn from said take-up roll means and feeding said yarn into said crimping chamber at a predetermined tension, said yarn between said take-up roll means and said feed means being subjected to a third tension dependent upon the rate of said feed means and the inherent shrinkage of said yarn after drawing, said take-up roll means isolating said first tension from said third tension whereby said first tension is maintained substantially constant in the face of variances in said third tension, tension responsive means interposed between said take-up roll means and said feed means for sensing said third tension, said tension responsive means being operatively interconnected with said feed means to vary the rate of said feed means if said third tension varies from said predetermined tension to maintain said third tension substantially equal to said predetermined tension, and cooling means interposed between said take-up roll means and said feed means for cooling said yarn prior to engagement by said feed means.
 2. The apparatus of claim 1 wherein said cooling means comprises a multipass air cooling station to maintain said yarn in contact with the surrounding air for a period to effect cooling.
 3. The apparatus of claim 1 wherein said cooling means comprises a cooling chamber having means for supplying water mist through which said yarn passes.
 4. Apparatus for crimping yarn comprising: draw rolls for engaging said yarn, said draw rolls being driven at such a rate as to apply to said yarn a first tension of such magnitude as to draw said yarn to a predetermined degree, take-up roll means disposed adjacent said draw rolls for receiving saId yarn exiting from said draw rolls, said take-up roll means positively engaging said yarn and being driven at such a rate as to apply to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls, a stuffer-crimper having a crimping chamber and feed means for receiving said yarn from said take-up roll means and feeding said yarn into said crimping chamber, said yarn between said take-up roll means and said feed means being subjected to a third tension dependent upon the rate of said feed means and the inherent shrinkage of said yarn after drawing, said take-up roll means isolating said first tension from said third tension whereby said first tension is maintained substantially constant in the face of variances in said third tension, and tension responsive means interposed between said take-up roll means and said feed means for sensing said third tension, said tension responsive means being operatively interconnected with said feed means to vary the rate of said feed means if said third tension varies from said predetermined tension to maintain said third tension and said predetermined tension substantially equal.
 5. The apparatus of claim 4 wherein said tension responsive means comprises a pivoted arm engaging said yarn and movable with the slackness of said yarn.
 6. The apparatus of claim 4 wherein said draw rolls are heated.
 7. The apparatus of claim 4 wherein said take-up roll means are operable independently of said draw rolls.
 8. A method of crimping yarn comprising the steps of: drawing said yarn between sets of draw rolls to a first tension, positively engaging said yarn immediately upon exit from said draw rolls and applying to said yarn a second tension of such magnitude as to minimize slippage of said yarn on said draw rolls, feeding said yarn into a crimping chamber at a third tension of predetermined level dependent upon the rate of yarn feeding and the inherent shrinkage of said yarn after drawing, said third tension being isolated from said first tension whereby said first tension is maintained substantially constant despite variances in said third tension, sensing the actual tension on the yarn between said positive engagement thereof upon exit from said draw rolls and said crimping chamber, comparing said actual tension to said predetermined third tension, and varying the rate of said feed means to keep said predetermined third tension and said actual tension substantially equal. 